This invention relates to fiber optics, and more particularly to fiber optic devices that perform image scanning or image displaying. Such devices in the past have included a single optical fiber which is supported rigidly at one end. That is, the other end is unsupported as in a cantilevered structure. The unsupported end of the fiber is thus free to move over a curved surface which approximates a plane if the displacement of the movable end of the fiber is small compared to the length of the fiber.
Such a structure has been utilized both as a display device and as an image scanning device. If the supported end of the fiber is coupled optically to a light emitting diode, then light is transmitted from the diode to the free end of the fiber. This light generates an image on the plane over which it moves when the modulating electrical signal for the light emitting diode is correlated with the scanning motion of the fiber. Conversely, the supported end of the fiber can be optically coupled to a photo diode. In that case, an image that is projected by some other apparatus onto a plane that the free end scans, is transmitted to the photo diode and converted to a time dependent electrical signal.
In the prior art, such optical scanning devices all used continuous motion scanning. Typically, a raster pattern was used. The continuous motion was achieved either electro-statically or electro-magnetically. Continuous electro-static motion was achieved, for example, by placing a charge on the fiber, and by placing the charged fiber between the plates of a parallel plate capacitor. Similarly, continuous electro-magnetic motion was achieved by placing a magnetic material on the fiber, and by placing the magnetized fiber between a pair of Helmholtz coils or other similar coil arrangement.
All of these prior art devices, however, are deficient in that they do not provide any means for positioning the moveable end of the fiber in discrete increments. That is, they only enable the movable end to be moved in a continuous scanning motion, such as a raster. If however, the movable end could be moved in discrete increments, it could be positioned much more accurately. Further, the scanning pattern of the movable end could be adopted to best suit the task at hand. For example, if information from only a portion of the entire scanning area were desired, the scanning pattern could be readily modified to cover only that portion. As another example, if a target were being tracked, the scanning pattern could simply lock onto the movement of the target.
Therefore, it is a primary object of the invention to provide an improved magnetic fiber optic device that can scan scenes in discrete increments.